Efforts to improve industrial plant efficiency have generated interest in making industrial plants relatively quickly and easily convertible from one industrial process to another. Convertibility of industrial plants permits plant managers to stay abreast of and provide for the demands of the marketplace. A very important component of virtually every industrial plant is conveyor systems. Therefore, the convertibility of conveyor systems is very important to the convertibility of industrial plants. In the conveyor system art, convertibility relates to accommodating articles having various sizes, shapes and physical characteristics.
One particular feature of convertibility is the ease by which a conveyor chain is removable from a conveyor beam. The easier and quicker it is to remove and change out a conveyor chain, the more convertible the industrial plant is.
Another important aspect of conveyor systems is interchangeability. As a conveyor line is converted from one configuration to another, it may be advantageous to utilize accessories supplied by various manufacturers depending on the article of manufacture to be run. Therefore, having a conveyor beam that is able to accommodate many varying accessories is critical to interchangeability and convertibility. It is also critical to provide a conveyor beam that is easy to retrofit with, for instance, existing conveyor equipment.
Extruded conveyor beams have been utilized for many years. Typically these beams have had, when viewed in longitudinal cross-section, sidewalls extending above and below a center section and flanges extending inwardly from the upper and lower ends of the sidewalls to carry conveyor chains. Typically, the conveyor chain will ride on top of the upper flanges while transporting an article to a selected destination, and is then inverted, riding on the lower flanges on the return trip, the lower flanges keeping the conveyor chain from falling out of the beam.
Generally, these beams have presented a symmetrical longitudinal cross section. This means that the sidewalls and flanges that extend upwardly from the center section have mirrored counter parts that extend downwardly from the center section such that the upper and lower sidewalls and flanges have exactly the same measurements.
This presents the disadvantage that, to remove the conveyor chain in order to retool the conveyor system, the beam must be dismantled at a selected location and the chain removed at that point, typically from an end section. Further, the replacement conveyor chain must then be inserted at the removal point and the beam reconnected. This process is difficult and time consuming, greatly increasing the costs associated with retooling a line.
A number of patents have attempted to deal with this problem with limited success. For instance, U.S. Pat. No. 4,961,492 to Wiseman et al. (“the '492 patent”) discloses the use of differing wearstrips, one that will permit the conveyor chain to freely be lifted out of the beam and the other that will securely hold the conveyor chain to the beam. The beam is designed such that the conveyor chain may freely be lifted out at any point, while the placement of the wearstrips determines where the conveyor chain will be freely removable. However, a disadvantage of the '492 patent is that the beam is taught to be symmetrical in cross-section from top to bottom such that the wearstrips must retain the conveyor chain in the beam when, for instance, inverted, and the wearstrips must structurally bear the weight of the inverted conveyor chain rather than the flange itself which typically comprises an extruded material such as aluminum ('492 patent, FIGS. 2, 5, col. 4, 42-55). Any subsequent failure of the conveyor equipment that causes a shutdown of the line can be very expensive, both in terms of repair costs and shutdown time. The '492 patent further teaches that the conveyor chain used has plastic protrusions designed to engage with the specially designed wearstrips to hold the conveyor chain to the beam ('492 patent, FIGS. 2, 5, col. 5, lines 26-33 and 62-68, and col. 7, lines 2-9). This is also undesirable because the conveyor chain is only maintained in the beam by plastic tabs rather than by a more robust means. In addition, the specially designed wearstrips add complexity and cost to the system, as do the specially designed conveyor chain pieces with the small plastic tabs. Still further, the '492 patent fails to teach or disclose the use of mounting recess capable of receiving many varying accessories or retrofitting to existing equipment (such as a double-T slot recess), located in the sides of the outer walls of the beam. Instead, the '492 patent only teaches the use of a single slot which will limit interchangeability and the ability to retrofit the beam to, for instance, existing equipment ('492 patent, FIG. 2, col. 4, lines 53-57).
U.S. Pat. No. 5,316,134 to Donohue (“the '134 patent”) has further tried to address this issue with limited success. The '134 patent discloses a conveyor system where the conveyor chain may be lifted out of the top of the beam while still holding the conveyor chain to the beam on the bottom of the beam. This method, like the '492 patent, discloses that the conveyor chain utilized has plastic protrusions designed to engage with the lower flanges ('134 patent, FIG. 1, col. 3, lines 15-21). However, as previously stated, it is undesirable to have the conveyor chain structurally maintained in the beam only by small plastic tabs. This conveyor chain also adds cost and complexity to the system. In addition, the '134 patent fails to provide any means by which to attach to the side of the beam, excluding the use of many standard accessories thereby severely limiting interchangeability, convertibility and the ability to retrofit the system. In fact, the '134 patent specifically teaches that no cavities or recesses may be located in the outer walls ('134 patent, FIG. 1, col. 1, lines 61-68). Further, the lower run of the conveyor chain is not freely accessible as it is enclosed on both sides by the downwardly extending sidewalls. ('134 patent, FIG. 1, col. 1, lines 67-68, col. 2, lines 1-4 and 7-13). This lack of accessibility can greatly increase the difficulty in servicing or repairing the system, for instance, if the conveyor chain is damaged.
U.S. Pat. No. 6,374,989 to van Dyke, Jr. et al. (“the '989 patent”) discloses the use of a double-T slot recess located on the outer wall of the conveyor beam. ('989 patent, FIGS. 4, 7, 8, 21 and 24). However, the '989 patent teaches away from having flanges that extend inward such that the conveyor chain may freely be lifted out of the beam from the top. ('989 patent, FIGS. 4, 7, 8, 21 and 24). For instance, the '989 patent teaches that the “edge walls 68 and 70 include ledge portions 76 and 78 (FIG. 4) located at a predetermined height above the conveyor belt 60 and projecting over the conveyor belt 60″ and that the “ledge portions 76 and 78 cooperate with the conveyor belt 60 to form a vertical confinement . . . and hold a sample tube.” ('989 patent, col. 5, lines 54-60.) This confinement is critical to the proper functioning of delivering tubes of “different heights and diameter.” ('989 patent, col. 5, line 61.) The '989 patent then, specifically teaches against removability of the conveyor chain from the top of the beam. In addition, although flanges are provided on the bottom of the beam, the conveyor chain disclosed in the '989 patent is never inverted such that the lower flanges of the beam are not utilized. Therefore, the '989 patent fails teach use of differing flanges from top to bottom such that the lower flanges engagingly hold the conveyor chain to the beam while the top flanges facilitate removal of the conveyor chain. Therefore, this configuration severely limits convertibility and interchangeability of the conveyor system.
What is desired is a conveyor system that allows easy removal of a conveyor chain while at the same time facilitates attachment of many various accessories and/or attachments to the side of the beam.
It is further desired to provide a conveyor system that provides a means of removeably engaging the conveyor chain to a beam that is simple, cost effective and structurally robust.
It is still further desired to provide a conveyor system that allows easy removal of a simple conveyor chain that is accessible on both the top and bottom run.
It is yet further desired to provide a conveyor system that minimizes the costs and time associated with repair and/or replacement of the various conveyor components.
It is still further desired to provide a conveyor system that facilitates retrofitting of newer and older conveyor equipment.